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Query: "author" (David O%C5%BEura) .

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101.
Izboljšanje učinkovitosti in informacijske vsebine gozdne inventure s stratificiranim vzorčenjem
David Hladnik, Milan Hočevar, 1989, original scientific article

Keywords: gozdna inventura, stratificiranje, sestojne karte
Published in DiRROS: 12.07.2017; Views: 4044; Downloads: 1799
.pdf Full text (1005,45 KB)

102.
103.
Presoja prostorskega stratificiranja za vzorčno ocenjevanje gozdnih zemljišč
David Hladnik, 2015, original scientific article

Abstract: Za vzorčno ocenjevanje rabe gozdnih zemljišč in pokrovnosti ter njunih sprememb na Slovenskem predlagamo stratificiranje prostorskih podatkov na podlagi tipologije gozdnih rastišč. Na podlagi karte rabe zemljišč in tipologije gozdnih rastišč smo ocenili prostorska merila variabilnosti za krajinske kazalce in jih primerjali s stratificiranjem po statističnih regijah. Ker gozd po površini prevladuje v 10 od 12 statističnih regij, te ne predstavljajo izhodišča za oblikovanje stratumov, s katerimi bi pojasnjevali razlike v variabilnosti deležev rabe zemljišč. S statističnimi regijami smo pojasnili 21 % skupne variance za ocenjevanje deležev kmetijske rabe in 17 % variance za delež gozda. Z razvrščanjem kilometrskih kvadratov po tipologiji gozdnih rastiščnih tipov je bil pojasnjen večji del variabilnosti kot v prostorskem merilu statističnih regij, vendar na račun velikega števila skupin oziroma 29 stratumov. Velike razlike v krajinskih kazalcih za te skupine gozdov ponazarjajo, da je prostorsko merilo za oblikovanje stratumov manjše od regionalnega.
Keywords: raba zemljišč, varianca rabe, varianca pokrovnosti, gozdna zemljišča, tipologija gozdnih zemljišč
Published in DiRROS: 12.07.2017; Views: 4522; Downloads: 2119
.pdf Full text (876,96 KB)

104.
Consistency of stand density estimates and their variability in forest inventories in Slovenia
David Hladnik, Laura Žižek, 2014, original scientific article

Abstract: The national estimates of forest resources in Slovenia are based on data aggregation from forest inventories conducted in forest management units of Slovenia Forest Service (SFS) and on the parallel forest inventory established within the Forest and Forest Ecosystem Condition Survey (FECS) as a continuation of international forest monitoring programme. Since the difference in sampling design and temporal dynamics of data collection is of key importance for inventories at the level of forest management units compared to large-area forest inventories, the consistency of stand densities was checked in both concepts. Comparing growing stock estimates in FECS on the systematic 4-km grid of sampling plots from SFS forest management planning, no overall significant differences in temporally comparable periods have been detected. We propose a basis enabling consistent estimates of structural forest characteristics at the national level for the process of forest inventory harmonization in Slovenia.
Published in DiRROS: 12.07.2017; Views: 4546; Downloads: 2459
.pdf Full text (920,10 KB)

105.
Zanesljivost volumenskih funkcij na primeru drevesne vrste smreke v Sloveniji
Gal Kušar, David Hladnik, Milan Hočevar, 2013, original scientific article

Abstract: Primerjali smo različne volumenske funkcije za ocenjevanje volumnov dreves. S pomočjo sekcijskih meritev (Newtonova metoda) smo izračunali prave ocene volumnov dreves 88 posekanih smrek na Pokljuki. Te smo uporabili za izdelavo regionalnih trovhodnih volumenskih funkcij, (dvovhodnih) deblovnic in tarif. Standardna napaka ocene povprečne vrednosti volumna drevesa je najmanjša pri trovhodnih volumenskih funkcijah (5,0 %), nato pri deblovnicah (11,7 %) in največja pri tarifah (15,1 %). Zanesljivost in uporabnost izdelanih regionalnih ter drugih volumenskih funkcij smo preverili na dveh hektarskih raziskovalnih ploskvah. Ugotovili smo, da s prirejenimi nemškimi deblovnicami smrekam določimo previsoke volumne. Ker volumne iz teh deblovnic uporabljamo tudi pri določanju prirejenih tarif na Slovenskem, je s takim postopkom določen tarifni razred z vsaj za 5 % previsokimi volumni dreves.
Keywords: volumenske funkcije, volumen dreves, lesna zaloga, smreka, Picea abies, Pokljuka
Published in DiRROS: 12.07.2017; Views: 4504; Downloads: 2178
.pdf Full text (791,99 KB)

106.
On the use of R programming language in the analyses of spatial data
Milan Kobal, Andrej Ceglar, Klemen Eler, Barbara Medved Cvikl, Luka Honzak, Primož Simončič, David Hladnik, 2013, original scientific article

Abstract: R is a powerful and increasingly popular programming language with strong graphical and presentation features and large expanŽdability. Although primarily intended for statistical computing, R has paved its way to the field of GIS through the development of specialized extension packages. It offers a wide range of functions at all GIS levels: data acquisition, data manipulation, graphical reŽpresentation and quantitative analysis. The paper presents R as an open source alternative to the existing commercial GIS software. It proves especially well when advanced quantitative methods on spatial data are needed (e.g. spatial modelling). We demonstrate R capabilities through spatial analysis of forest area in Snežnik (South Slovenia), where the possibilities of data import, conversion and export into various GIS formats and possibilities of geostatistics, spatial modelling and spatial visualization are demonstrated.
Published in DiRROS: 12.07.2017; Views: 5181; Downloads: 2707
.pdf Full text (2,43 MB)

107.
Ocenjevanje gozdnatosti v zasnovi gozdne inventure na Slovenskem
David Hladnik, Laura Žižek, 2012, original scientific article

Keywords: gozdnatost, ocenjevanje, gozdna inventura, vzorčne mreže, ortofoto, Slovenija
Published in DiRROS: 12.07.2017; Views: 4542; Downloads: 2001
.pdf Full text (427,22 KB)

108.
Ocenjevanje natančnosti deblovnic in volumenskih funkcij
David Hladnik, Milan Kobal, 2012, original scientific article

Abstract: Primerjali smo postopke za ocenjevanje volumna debeljadi jelke na podlagi Huberjevega, Smalianovega in Newtonovega obrazca. Podatke za primerjavo smo dobili z interpolacijo kubičnih zlepkov na podlagi merjenja posekanih dreves. Newtonov in Huberjev postopek sta bila najnatančnejša pri ocenjevanju volumnovstarih jelk (starost do 200 let, povprečni premer 59 cm). Na podlagi izračunanih volumnov smo ocenjevali volumne stoječih dreves v sklopu gozdne inventure. Slovenske Čoklove tarife (1959) so se kljub svoji preprosti zasnovi izkazale s sprejemljivo natančnostjo (povprečno odstopanje v odstotkih od povprečnega volumna < 1 %, R2=0.87). Delež pojasnjene variabilnosti volumnov dreves se je povečal za 5 % pri dvovhodnih deblovnicah in za 11 % pri triparametrskih volumenskih funkcijah.
Keywords: volumen debeljadi, tarife, volumenske funkcije, jelka, Abies alba Mill.
Published in DiRROS: 12.07.2017; Views: 4374; Downloads: 1869
.pdf Full text (882,11 KB)

109.
Stand diversity in the Dinaric fir-beech forests
Milan Kobal, David Hladnik, 2009, original scientific article

Abstract: Data from forest research and permanent sampling plots were used to quantify stand structure and forest diversity in uneven-aged Dinaric silver fir and beech forest at the level of forest management unit. The study examined the indicators that are expected to be used in the monitoring of biodiversity and the favourable conservation status of forest habitat types in Natura 2000 sites. By comparing the present and past stand structures, it was possible to establish the developmental dynamics of the stands and the changes of structure indices of the forest stands on the 2-hectare research plots in the last 50 years. We adopted the indicators for the assessment of biotic and stand structure diversity based on tree species composition, stand densities, mean DBH and coefficient of variation, species and DBH-based Shannonćs index, spatial mingling and size differentiation of trees on the permanent sampling plots. The indicators confirmed stand structural diversity in four forest management classes of uneven-aged Dinaric fir-beech forests in the Leskova dolina (valley) of the Sneznik-Javorniki high Karst region. Continuous forest inventory and the presented indicators of stand structure and diversity may potentially represent the framework for the monitoring of the favourable conservation status of forest habitat types.
Published in DiRROS: 12.07.2017; Views: 4157; Downloads: 1824
.pdf Full text (891,28 KB)

110.
Artificial energy inputs into spruce lowland forests in suburban landscapes in Slovenia
Janez Pirnat, David Hladnik, 2009, original scientific article

Abstract: Slovene forestry is concerned with nature conservation, but in the past, the species variety of forests has often been changed and, similarly as elsewhere in Europe, the share of forest with artificial dominance of Norway spruce increased. Based on the spatial model of landscape structure, we estimated the arrangement in conservation of suburban forests in eight Slovene macro regions. In the area of town Kočevje, we assessed artificial energy inputs in the forests lying within one kilometre large area used by inhabitants for daily recreation. In this area, 65 % of forests were categorized as forests with artificial dominance of Norway spruce.
Published in DiRROS: 12.07.2017; Views: 4410; Downloads: 1942
.pdf Full text (377,40 KB)

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